Amsonia tabernaemontana

Stems erect (ascending), 27–102 cm, glabrous (sparsely pubes­cent); branches borne on distal portion of stem, much exceeding infructescence. Leaves: petiole 1.5–7(–9) mm, sparsely to moderately pubescent or gla­brous; blades not heteromor­phic; stem leaf blades lanceolate to narrowly lanceolate, ovate, narrowly elliptic, or elliptic, (2.5–)3.3–12.5(–14.4) cm × (8–)11–50(–65) mm, margins entire to subentire, not to moderately revo­lute, ciliate or not, apex acuminate to acute (rarely with a rounded tip), surfaces sparsely pubescent abax­ially (and sparsely scabrous or short-pubescent adax­ially) or gla­brous; branch leaf blades similar to stem leaf blades. Flowers: sepals deltate to narrowly deltate, (0.4–)0.5–1.8(–2.3) mm; corolla tube bluish (rarely to lilac), some­times greenish above, (5–)6–8(–8.8) mm, lobes pale blue (rarely to dark or lilac-blue or white), (5–)6–9.8(–12) mm, outer surface of corolla with 5 patches of long trichomes at corolla lobe bases and distal part of tube (very rarely glabrate). Follicles erect to pendulous (spreading), (5–)7–15 cm × 2.1–4(–4.2) mm, apex acu­minate (acute), glabrous. Seeds (5–)5.5–10.8 × (1.2–)1.5–2.4(–3.3) mm.

Distribution

c, e United States.

Discussion

Varieties 4 (4 in the flora).

Amsonia tabernaemontana encompasses a great deal of morphological diversity, particularly in leaf size and shape and sepal indument and length, which is to some extent geographically correlated; therefore, the recogni­tion of varieties seems desirable. However, the varieties are not well differentiated and tend to blend into one another, especially where their ranges overlap.

Selected References

None.

Lower Taxa

Amsonia tabernaemontana var. illustris, Amsonia tabernaemontana var. repens, Amsonia tabernaemontana var. salicifolia, Amsonia tabernaemontana var. tabernaemontana

Key

1	Stems ascending (erect); stem leaf blades (2.5–)3.3–7.4 cm; sepals usually sparsely pubescent; e Texas, Oklahoma.	Amsonia tabernaemontana var. repens
1	Stems erect; stem leaf blades (4–)6.5–12(–14.4) cm; sepals pubescent or glabrous; widespread in se to sc United States.	> 2
2	Sepals narrowly deltate or less often deltate, (0.5–)0.9–1.6(–1.9) mm, usually sparsely to moderately long-pubescent in flower (often becoming glabrous or glabrate in fruit); Illinois, Arkansas to Kansas, Oklahoma.	Amsonia tabernaemontana var. illustris
2	Sepals deltate (seldom narrowly deltate), (0.4–)0.5–1.1(–1.6) mm, glabrous (glabrate with rare single hairs); widespread.	> 3
3	Stem leaf blades lanceolate to ovate, narrowly elliptic, or elliptic, (5.3–)8–12(–14) cm × (17–)24–50(–65) mm.	Amsonia tabernaemontana var. tabernaemontana
3	Stem leaf blades narrowly lanceolate to lanceolate (or narrowly elliptic when young), (4–)6.5–10(–11.5) cm × 10–22(–25) mm.	Amsonia tabernaemontana var. salicifolia